FIG. 4 and FIG. 5 show a conventional faucet structure and disclose a body 5 of the faucet assembled with a control valve 5a. The control valve 5a has a valve rod 50 extending from the body 5 for connecting with a rotation control device 9. The rotation control device 9 includes a shell 6 and a handle 7. The shell 6 has a slot 61 and the handle 7 has a connecting part 71. The shell 6 covers the body 5 and the connecting part 71 of the handle 7 is connected to the valve rod 50 by passing through the shell 6 via the slot 61 and fixed on the valve rod 50 by a screw 8. Thus, when the handle 7 is rotated to any directions, a ceramic mobile valve plate located inside of the control valve 5a will be moved simultaneously through the valve rod 50, and the positional variation of the ceramic mobile valve plate determines a mixing ratio of cool and hot water to flow out of the body 5.
For purposes of easy installations, an inner diameter of the connecting part 71 of the hand 7 is usually larger than an outer diameter of the valve rod 50, and the handle 7 is fixed only with the screw 8. However, this installation will cause the handle 7 to loosen from the valve rod 50 due to the screw 8 is loosened after a long period of operation. Once the handle 7 is loosened, the faucet becomes hard to control and the handle 7 is easy to collide with an inner wall of the slot 61 during rotation that cause damages to the shell 6 and the handle 7 both.
Moreover, in consideration of reducing material costs and manufacturing difficulties, the shell 6 is cast in weaker zinc alloy. Thus, as shown in FIG. 4, the inside of the shell 6 have to form with two reinforced plates 62. However, regardless of this effort, the shell 6 still cannot endure a larger impact because of the weaker structure of the shell 6.
Furthermore, in order to prevent erosion and to improve the product quality, the outer surface of the shell 6 is plated with a layer of chromium but the adhesion between chromium and zinc alloy is not compatible, the chromium plated on the surface of the shell 6 is easy to fall off due to collision, or peel off due to oxidation.